FR 2 639 139 A1 describes a nuclear fuel rod spacer grid for a light water reactor, comprising two grid parts with dimples and one grid part with springs, which grid parts can be offset for the longitudinal insertion of the rods through the grid or aligned in order to clamp the rods between the grid parts. The grid comprises an outer frame produced in two parts for holding the grid parts in the rod clamping configuration.
The use of this grid requires a special tool for holding the grid parts in the rod insertion configuration and in the rod clamping configuration, and for fixing the frame.